slide_canvas = function(pane_index, dir)
	return function()
		end_frame()
		if dir == 'right' then
			for i=1,40 do
				print(Current_time, i)
				love.graphics.rectangle('fill', i*10,0, 30, App.screen.height)
				end_frame()
			end
		elseif dir == 'left' then
			for i=20,1,-1 do
				print(i)
				love.graphics.line(i*50,0, i*50, App.screen.height)
				end_frame()
			end
		end
	end
end

-- update any in-progress animations
-- return whether any work remains
draw_next_frames_of_animations = function()
	local a = Animations_in_progress
	for i=#a,1,-1 do
		if coroutine.status(a[i].co) == 'dead' then
			table.remove(a, i)
		else
			local status, err = coroutine.resume(a[i].co)
			if status == false then error(err) end
		end
	end
	return #a > 0
end

-- Pause a drawing called by animate().
end_frame = function()
	coroutine.yield()
end

-- Intermediate state during animations.
Animations_in_progress = {}

-- A debugging aid to help animate intermediate results within f.
-- Pause animation in the current frame using loiter().
-- Try to only have one such call in your program.
-- You can have multiple, but things might get confusing if one of them indirectly calls the other,
-- or more generally if a single function ever loiters sometimes under the call tree of one and sometimes under the other.
enable_loiter = function(f, ...)
	local args = {...}
	Error_with_callstack = nil
	local co = coroutine.create(
						function()
							xpcall(function()
											f(unpack(args))
										end,
										save_callstack)
						end)
	coroutine.resume(co, ...)
	if Error_with_callstack then
		error(Error_with_callstack)
	end
	table.insert(Debug_animations_in_progress, {co=co, next_run=Current_time+0.3})
end

				animate(slide_canvas(Current_pane_index+1, 'right'))

				animate(slide_canvas(Current_pane_index-1, 'left'))

				animate(slide_canvas(Current_pane_index-1, 'left'))

	draw_next_frames_of_animations()

-- Internal helper for animate()

-- Internal helper for animations.

end

end

-- Can only be called from functions invoked using `animate()`.

-- Can only be called from functions invoked using `enable_loiter()`.

end

end

-- A debugging aid to help animate intermediate results within f.
-- Pause animation in the current frame using loiter().
-- Try to only have one such call in your program.
-- You can have multiple, but things might get confusing if one of them indirectly calls the other,
-- or more generally if a single function ever loiters sometimes under the call tree of one and sometimes under the other.

-- Animate 'f' by smearing its work across multiple frames.
-- Pause animation in the current frame using end_frame().

	table.insert(Debug_animations_in_progress, {co=co, next_run=Current_time+0.3})
end

	table.insert(Animations_in_progress, {co=co})
end